Rapidly screening out refractory metallic alloys with high glass-forming ability by laser surface remelting

Compared with conventional metallic glasses, refractory metallic glasses (RMGs) with a mass of refractory element(s), high glass-transition temperature (Tg) and outstanding mechanical properties (like ultrahigh strength, high hardness and good wear resistance) exhibit fascinating potential applications in high temperature field. However, the development of RMGs is painfully slow, and one of the key problems is the lack of rapid and convenient way to screen out high glass-forming refractory alloys. In this study, a method for rapid evaluation of glass forming ability (GFA) based on laser surface remelting was provided. The high-efficiency screening-out method was validated in a classical glass-forming model system of Ni-Nb binary refractory alloys. The effects of different laser parameters on the glass formation and phase evolution were investigated by experimental analysis and finite element simulation. By correlating thermal history of the laser treatment with glass formation, the alloys with high GFA in Ni-Nb system was screened out rapidly. The screening-out efficiency of the novel method can be improved one order of magnitude, compared with that of the conventional techniques, and the materials cost can be reduced, especially for RMGs. The revealed formation mechanism of glassy and crystalline phases in time and spatial distributions influenced by thermal history under multi-scanning laser treatment can provide a significant insight in the construction of the bulk-metallic-glass materials and the related composite ones by laser additive manufactory.